RU2643409C2 - Control device for steering - Google Patents

Abstract

FIELD: transportation.

SUBSTANCE: control device for steering is proposed, in which, using the distribution coefficients (GF₁, GF₂, GF₃, GF₄) based on the difference between axial forces, lateral acceleration (Ga), vehicle speed (V), turn angle (δ) at steering and angular steering speed (dδ/dt); the control parameter calculation module (11) distributes the axial force (T_FF) of direct coupling and the axial force (T_FB) of back coupling and specifies the final axial force. The control parameter calculation module (11) applies the reaction force at steering based on the specified final axial force. Control devices for steering are also proposed.

EFFECT: enabling the possibility of applying a more appropriate reaction force at steering.

5 cl, 19 dwg

Description

FIELD OF THE INVENTION

[0001] The present disclosure relates to a steering control device from a steering system by wire, in which the steering wheel and steering wheels are mechanically separated from each other.

State of the art

[0002] As a technology for a steering control device, for example, Patent Document 1 for one technology is provided.

In PLT 1, a motor for generating a reaction force is driven based on a steering response control amount based on a steering angle while steering and a control amount calculated by multiplying an electric current of the steering engine by a predetermined gain. Thus, in PLT 1, the influence of external force exerted on the steered wheels is reflected in the reaction force during taxiing.

List of bibliographic references

Patent documents

[0003] PLT 1. JP 2000-108914 A

SUMMARY OF THE INVENTION

Technical challenge

[0004] However, in the above technology, the engine for generating the reaction force is driven based on the steering reaction force control amount based on the steering angle when steering and the control amount calculated by multiplying the electric current of the steering engine by a predetermined gain. Therefore, in the above technology, for example, in the case where the accuracy of the control force of the reaction force when taxiing based on the steering angle when taxiing is deteriorated, there is a possibility that the reaction force when taxiing is inappropriate.

The present disclosure is made taking into account the above circumstances and has the task of ensuring the possibility of applying a more appropriate reaction force when taxiing.

The solution of the problem

[0005] In order to solve the above problem, in one embodiment of the present disclosure, the axial direct coupling force and the axial feedback force are distributed with a distribution coefficient to define the final axial force. Then, in one embodiment of the disclosure, a taxi reaction is applied based on the final axial force that is specified. In this case, when there is a difference in axial forces between the axial direct coupling force and the axial feedback force, the distribution coefficient of the axial direct coupling force is made smaller when the absolute value of the axial force difference is equal to or greater than the predetermined value than the distribution coefficient in the case when the absolute value of the difference between the axial forces is less than a predetermined value.

Advantages of the Invention

[0006] In one embodiment of the present disclosure, since the axial direct coupling force and the axial feedback force are distributed with a distribution coefficient based on the difference in axial forces, lateral acceleration, vehicle speed, steering angle and taxiing speed, it is possible mix the axial force of the direct coupling and the axial force of the feedback in a more appropriate way.

Accordingly, in one embodiment, a more appropriate reaction force when taxiing can be applied.

Brief Description of the Drawings

[0007] FIG. 1 is a conceptual view illustrating a configuration of a vehicle A;

FIG. 2 is a block diagram illustrating a configuration of a control parameter calculating unit 11;

FIG. 3 is a block diagram illustrating a configuration of a reaction force target current calculating unit 11B;

FIG. 4 is a block diagram illustrating a configuration of an axial direct coupling axial force calculating unit 11Ba;

FIG. 5 is a view illustrating coefficients in an expression for calculating an axial force Th of a pinion gear;

FIG. 6 is a graph representing a control map M1;

FIG. 7 is a graph representing a control map M2;

FIG. 8 is a graph representing the relationship between the steering angle δ when taxiing and the reaction force when taxiing.

FIG. 9 is a graph representing a control map M3;

FIG. 10 is a graph representing a control card M4;

FIG. 11 is a block diagram illustrating a configuration of an axial feedback force calculating unit 11Bb;

FIG. 12 is a graph representing an axial force of a transverse G, an axial force of an electric current, an axial force of an angular yaw rate, and an actual axial force of a steering rack;

FIG. 13 is a graph representing the mixed axial force T _BR and the actual axial force of the steering rack.

FIG. 14 is a graph representing a control card M5;

FIG. 15 is a graph representing a control card M6;

FIG. 16 is a graph representing a control card M7;

FIG. 17A and FIG. 17B are graphs representing control cards M8a and M8b;

FIG. 18 is a graph representing a control card M9;

FIG. 19 is a graph representing a control card M10.

Description of Embodiments

[0008] The following describes embodiments of the present disclosure with reference to the drawings.

Configuration

Vehicle A is a vehicle including a steering control device from a wire steering system in which a steering wheel 1 and front wheels 2 (hereinafter, also referred to as "steered wheels") are mechanically separated, in one embodiment real disclosure.

FIG. 1 is a conceptual view illustrating a configuration of a vehicle A in one embodiment of the present disclosure.

As illustrated in FIG. 1, vehicle A is configured to include a steering angle sensor 3, a steering angle sensor 4, a vehicle speed sensor 5, a transverse G sensor 6, a yaw rate sensor 7, and a gear shift position sensor 12.

The steering angle sensor 3 when taxiing is configured to detect a steering angle δ when steering the steering wheel 1. As a method for detecting a steering angle δ when steering, for example, a method for calculating an angle based on a steering shaft rotation amount can be used. Then, the steering angle sensor 3 during taxiing is configured to output a signal (hereinafter, also referred to as a "detection signal") representing the detection result to the control parameter calculation unit 11, which is described below.

[0009] The rotation angle sensor 4 is configured to detect a steering angle θ of the steered wheels 2. As a method for detecting a rotation angle θ, for example, a method of calculating an angle based on a gear amount for a steering gear rack can be used. Then, the angle sensor 4 is configured to output a detection signal to the control parameter calculation unit 11.

The vehicle speed sensor 5 is configured to detect a vehicle speed V for the vehicle A. Then, the vehicle speed sensor 5 is configured to output a detection signal to the control parameter calculation unit 11.

The transverse G sensor 6 is configured to detect lateral acceleration Gy, which should be applied to the vehicle A (a value characterizing the state of the vehicle A, which varies depending on the lateral force Fd on the tires applied to the steered wheels 2). Then, the transverse sensor G 6 is configured to output a detection signal to the control parameter calculation unit 11.

The yaw rate sensor 7 is configured to detect the yaw rate γ of the vehicle A (a value characterizing the state of the vehicle A, which varies depending on the lateral force Fd on the tires applied to the steered wheels 2). Then, the yaw rate sensor 7 is configured to output a detection signal to the control parameter calculation unit 11.

It should be noted that the transverse G sensor 6 and the yaw rate sensor 7 are located in the spring (vehicle body).

The gearbox position sensor 12 is configured to detect a position of a gear lever on a gearbox. As a gearshift lever position, for example, D-range, R-range (reverse position) and P-range are included. Then, the gearbox shift position sensor 12 is configured to output a detection signal to the control parameter calculation unit 11.

[0010] In addition, the vehicle A is configured to include a steering control module 8 and a reaction force control module 9.

The rotation control module 8 is configured to include a rotary motor 8A, a rotation current detection module 8B, and a rotary motor drive module 8C.

The rotary motor 8A is connected to the gear shaft 10 via a gearbox. Then, the rotary engine 8A is driven by the rotary engine driving unit 8C to move the steering gear rack to the left or right through the gear shaft 10. Thus, the rotary motor 8A rotates the steered wheels 2. As a method of driving the rotary motor 8A, for example, a method for controlling electric current flowing through the rotary motor 8A (hereinafter, also referred to as "electric current during rotation", can be used )

[0011] The turning current detection module 8B is configured to detect an electric current when turning (a value characterizing the state of the vehicle A, which varies depending on the lateral force Fd on the tires applied to the steered wheels 2). Then, the rotation current detection module 8B is configured to output the detection signal to the rotary motor driving module 8C and the control parameter calculating module 11.

The rotary motor driving unit 8C is configured to control the electric current when the rotary motor 8A is rotated based on the target electric rotational current calculated by the control parameter calculating unit 11, so that the electric rotational current detected by the rotational current detection unit 8B, corresponds to the target electric current when turning. Thus, the rotary motor driving unit 8C drives the rotary motor 8A. The target electric current during rotation is the target value of the electric current flowing through the rotary motor 8A.

[0012] The reaction force control unit 9 is configured to include a motor 9A for generating a reaction force, a reaction force current detecting unit 9B, and a motor driving unit 9C for generating a reaction force.

A motor 9A for generating a reaction force is connected to the steering shaft via a gearbox. Then, the engine 9A for generating the reaction force is driven by the engine driving unit 9C for generating the reaction force in order to apply torque to the steering wheel 1 through the steering shaft. Accordingly, the engine 9A for generating a reaction force generates a reaction force when taxiing. As a method of driving an engine 9A to generate a reaction force, for example, a method for controlling an electric current flowing through an engine 9A to generate a reaction force (hereinafter, also referred to as "reaction force electric current") can be used.

The reaction force current detection unit 9B is configured to detect an electric current of the reaction force. Then, the reaction force current detection unit 9B is configured to output the detection signal to the engine driving unit 9C to generate the reaction force and the control parameter calculation unit 11.

The engine driving unit 9C for generating the reaction force is configured to control the electric current of the reaction force of the engine 9A to generate the reaction force based on the target electric current of the reaction force calculated by the control parameter calculating unit 11, so that the electric current of the reaction force detected by the module 9B, detection of the reaction force current corresponds to the target electric current of the reaction force. Accordingly, the engine driving unit 9C for generating the reaction force drives the engine 9A to generate the reaction force. The target electric current of the reaction force is the target value of the current flowing through the motor 9A to form the reaction force.

[0013] In addition, the vehicle A includes a control parameter calculating unit 11.

FIG. 2 is a block diagram illustrating a configuration of a control parameter calculating unit 11.

As illustrated in FIG. 2, the control parameter calculating module 11 is configured to include a target rotation angle calculating section 11A, a reaction force target current calculating section 11B, and a rotation target calculating section 11C.

The target rotation angle calculating unit 11A is configured to calculate the target rotation angle θ *, which is the target value of the rotation angle θ (rotation angle of the gear shaft 10), based on the steering angle δ detected by the steering angle sensor 3 and the speed V of the vehicle detected by the vehicle speed sensor 5. As a method of calculating the target steering angle θ *, for example, a method of using the multiplication value obtained by multiplying the steering angle δ by taxiing by an adjustable gear ratio of the steering angle δ and the steering angle θ is provided. Then, the target rotation angle calculating unit 11A is configured to output the calculation result to the target reaction force calculating unit 11B.

The reaction force target current calculating unit 11B is configured to calculate the reaction force target electric current based on the target rotation θ * calculated by the target rotation angle calculating module 11A, the vehicle speed V detected by the vehicle speed sensor 5, and the electric current when turning detected by the rotation current detection unit 8B. Then, the reaction force target current calculating unit 11B is configured to output the calculation result to the reaction force control unit 9 (engine driving unit 9C to generate the reaction force).

[0014] Here, the configuration of the reaction force target current calculating unit 11B is described.

FIG. 3 is a block diagram illustrating a configuration of a reaction force target current calculating unit 11B.

As illustrated in FIG. 3, the target reaction force current calculating unit 11B is configured to include an axial direct axial force calculating unit 11Ba, an axial feedback force calculating unit 11Bb, an axial feedback force correction unit 11Bf, a finite axial force calculating unit 11Bc, a force converting unit 11Bd steering reaction and axial force; and a module 11Be for calculating the target current of the reaction force.

FIG. 4 is a block diagram illustrating a configuration of an axial direct coupling force calculating unit 11Ba.

As illustrated in FIG. 4, the axial direct coupling force calculating unit 11Ba is configured to calculate the steering reaction force as the axial direct coupling force T _FF according to expression (5), which will be described later, based on the steering angle δ detected by the steering angle sensor 3 at taxiing, and the vehicle speed V detected by the vehicle speed sensor 5. Then, the direct axial force calculating unit 11Ba is configured to output the calculation result to the final axial force calculating unit 11B (see FIG. 2).

[0015] FIG. 5 is a view illustrating coefficients in an expression for calculating an axial force Th of a pinion gear.

Here, an expression of the relationship between the angle of rotation of the gear θ and the axial force Th of the pinion gear is represented by the following expression (1) based on the equation of motion of the vehicle including a steering mechanism in which the steering wheel 1 and the steering wheels 2 are mechanically connected. As an angle θ of rotation of the shaft gear, an angle of rotation of the gear shaft 10 is provided as an example. Specifically, the angle of rotation of the gear is set equal to the multiplication value obtained by multiplying the angle of rotation δ when taxiing and the adjustable gear ratio of the angle δ of rotation when taxiing and the angle θ of rotation. In addition, as an axial force Th of the pinion gear, as an example, a steering reaction force applied to the steering wheel 1 is provided. The first element on the right side of the following expression (1) is a damping element representing a component based on the angular rotation speed dθ / dt gears in the components included in the axial force Th of the drive gear. In addition, the second element on the right side is an inertial element representing a component based on the angular acceleration d ² θ / dt ^{2 of the} rotation of the gear in the components included in the axial force Th of the drive gear. Additionally, the third element on the right side is a proportional element representing a component based on the lateral force Fd on the tires (angle of rotation θ of the gear) in the components included in the axial force Th of the pinion gear.

[0016]

As illustrated in FIG. 5, Ks represents the stiffness of the pinion gear, Cs represents the viscosity of the pinion gear, Jr represents the inertia of the rack, and Cr represents the viscosity of the rack.

In addition, in the above expression (1), the second element on the right side, which is an inertial element, includes many noise components and they must be removed, since they lead to oscillation for the result of calculating the axial force Th of the pinion gear. In addition, the lateral force Fd on the tires can be represented by Fd = f (V) * θ as an element depending on the angle of rotation θ of the gear and the speed V of the vehicle. As f (V), for example, a function is provided that varies depending on the vehicle speed V. Accordingly, expression (1) can be represented by the following expression (2).

[0017] FIG. 6 is a graph representing a control map M1.

Here, as a method of setting the variable f (V), for example, a method of reading the variable f (V) corresponding to the absolute value of the vehicle speed V from the control card M1 can be used. As a control map M1, as an example, a map is provided in which the variables f (V) corresponding to the absolute values of the vehicle speeds V are registered. Specifically, as illustrated in FIG. 6, on the control map M1, when the absolute value of the vehicle speed V is 0, the variable f (V) is set equal to the first predetermined value (for example, 0.0). In addition, in the range in which the absolute value of the vehicle speed V is equal to or greater than the first predetermined vehicle speed V ₁ (> 0), the variable f (V) is set equal to the second predetermined value (> the first predetermined value, for example, 1.0 ) regardless of the absolute value of the vehicle speed V. In addition, the M1 control map, in a range in which the absolute value of the velocity V of the vehicle is equal to or greater than 0 and less than the first predetermined speed V ₁ of the vehicle, a variable f (V) linearly increases according to the absolute value of the angular dθ / dt rotation speed. Specifically, on the control map M1, in a range in which the absolute value of the vehicle speed V is equal to or greater than 0 and less than the first predetermined vehicle speed V ₁ , the variable f (V) is set according to a linear function representing the relationship between the absolute value of the vehicle speed V means and variable f (V). In a linear function, when the absolute value of the vehicle speed V is 0, the variable f (V) is set equal to the first specified value (0,0), whereas when the absolute value of the vehicle speed V is the first specified speed V ₁ of the vehicle, the variable f (V) is set equal to the second predetermined value (1.0). Accordingly, when the absolute value of the vehicle speed V is less than the first predetermined vehicle speed V ₁ , the axial direct coupling force calculating unit 11Ba makes the absolute value of the proportional component smaller (decreases) as the absolute value of the vehicle speed V becomes smaller. In addition, when the absolute value of the vehicle speed V is equal to or greater than the first predetermined vehicle speed V ₁ , the axial direct force calculating unit 11Ba does not reduce the absolute value of the proportional component regardless of the absolute value of the vehicle speed V.

[0018] Additionally, expression (2) can equivalently be represented as the following expression (3)

where P and I represent the control parameters, ζ represents the damping coefficient, and ωn represents the natural frequency. As a method of specifying ζ and ωn, for example, a method of specifying using a calculated value or an identification method from an experimental result can be used.

Therefore, the axial force Th of the pinion gear, which is the steering reaction force generated in the steering wheel 1, can be represented by the following expression (4) based on the expression (3)

[0019] Then, as a method of calculating the direct axial force T _FF based on the above expression (4), which is an arithmetic expression of the axial force Th of the pinion gear, in one embodiment of the present disclosure, the following expression (5) is used.

T _FF = P * P ₁ * P ₂ (s + 2 * ζ * ωn) / (s ² + 2 * ζ * ωn * s + ωn ² ) dδ / dt + I * (s + 2 * ζ * ωn) / (s ² + 2 * ζ * ωn * s + ωn ² ) * f (V) * δ + damping component for correction

= damping component * P ₁ / P ₂ + proportional component + damping component for correction ... (5)

However, the damping component is P (s + 2 * ζ * ωn) / (s ² + 2 * ζ * ωn * s + ωn ² ) dδ / dt, and the proportional component is I * (s + 2 * ζ * ωn) / (s ² + 2 * ζ * ωn * s + ωn ² ) * f (V) * δ. In addition, the damping component for correction is a damping component based on the angular taxiing speed dδ / dt and generates a reaction force when taxiing in the opposite direction relative to the direction of the angular taxiing speed dδ / dt.

[0020] FIG. 7 is a graph representing a control map M2.

Here, as a method for setting the gain P ₁ , for example, a method for reading the gain P ₁ corresponding to the absolute value of the angular steering speed dδ / dt from the control card M2 can be used. As a control card M2, as an example, a card is provided in which amplifications P ₁ corresponding to the absolute values of the angular steering speed dδ / dt are registered. Specifically, as illustrated in FIG. 7, on the control map M2, when the angular steering speed dδ / dt is 0, the gain P ₁ is set to a third predetermined value (for example, 1.0).

In addition, in the range in which the absolute value of the angular velocity dδ / dt of taxiing is equal to or greater than the first preset angular velocity dδ ₁ / dt of taxiing, the gain P ₁ is set to the fourth preset value (<third preset value, for example, 0.5) independently of the absolute value of the angular velocity dδ / dt of taxiing. Additionally, on the control map M2, in a range in which the absolute value of the angular velocity dδ / dt of taxiing is equal to or greater than 0 and less than the first predetermined angular velocity dδ ₁ / dt of taxiing, the gain P ₁ linearly decreases according to the absolute value of the angular velocity dδ / dt of taxiing . Specifically, on the control map M2, in a range in which the absolute value of the angular velocity dδ / dt of steering is equal to or greater than 0 and less than the first predetermined angular velocity dδ ₁ / dt of steering, the gain P ₁ is set in accordance with a linear function representing the relationship between the absolute the value of the angular velocity dδ / dt taxiing and gain P ₁ . In the linear function, the gain P ₁ is set equal to the third preset value (1.0) when the angular speed dδ / dt of taxiing is 0, while the gain P ₁ is set to the fourth preset value (0.5) when the absolute value of the angular velocity dδ / taxiing dt is the first predetermined angular steering speed dδ ₁ / dt. Accordingly, the axial direct coupling force calculating unit 11Ba sets the absolute value of the damping component smaller (corrects) as the absolute value of the angular speed dδ / dt of steering becomes larger when the absolute value of the angular speed dδ / dt of steering is less than the first given angular velocity dδ ₁ / dt taxiing. Additionally, the axial direct coupling force calculating unit 11Ba does not correct the absolute value of the damping component based on the gain P ₁ regardless of the absolute value of the angular velocity dδ / dt of taxiing, when the absolute value of the angular velocity dδ / dt of taxiing is equal to or greater than the first specified angular velocity dδ ₁ / dt taxiing.

[0021] FIG. 8 is a graph representing the relationship between the steering angle δ when taxiing and the reaction force when taxiing. This graph represents each steering control device (each of the steering control device from a mechanical system in which the steering wheel 1 and the steered wheels 2 are mechanically engaged, and the steering control device from the steering system by wire, which does not take into account the saturation of the damping component). In the steering control device from the mechanical system, as the angular speed dδ / dt of the steering increases, the damping component, which is included in the steering reaction, is saturated. Accordingly, in a steering control device of a mechanical system, as illustrated in FIG. 8, when the damping component is saturated, the shape of the Lissajous figure, including the angle of rotation δ when taxiing and the reaction force when taxiing, becomes constant regardless of the absolute value of the angular velocity dδ / dt of taxiing. However, in the steering control device from the steering system by wire, which does not take into account the saturation of the damping component included in the reaction force during taxiing, the taxiing reaction force continues to increase according to the increase in the angular steering speed dδ / dt. On the contrary, the control parameter calculating module 11 in one embodiment of the present disclosure sets the absolute value of the damping component lower as the absolute value of the angular velocity dδ / dt of the taxi becomes larger. Therefore, the control parameter calculating module 11 in one embodiment of the present disclosure allows suppressing an increase in the absolute value of the damping component when the angular steering speed dδ / dt is large. Therefore, the control parameter calculating unit 11 in one embodiment of the present disclosure allows suppression of an excessive damping component. Accordingly, the control parameter calculating module 11 in one embodiment of the present disclosure allows for a more appropriate taxiing feel.

[0022] FIG. 9 is a graph representing a control map M3.

In addition, as a method for setting gain P ₂ , for example, a method for reading gain P ₂ corresponding to the absolute value of vehicle speed V from the control card M3 can be used. As a control card M3, as an example, a card is provided in which amplifications P ₂ corresponding to the absolute values of the vehicle speed V are registered. Specifically, as illustrated in FIG. 9, on the control map M3, when the absolute value of the vehicle speed V is 0, the gain P ₂ is set to a fifth predetermined value (for example, 0.5). Additionally, in the range in which the absolute value of the vehicle speed V is equal to or greater than the second predetermined vehicle speed V ₂ (> 0), the gain P ₂ is set to the sixth predetermined value (> the fifth preset value, for example, 1.0) regardless absolute value of vehicle speed V. In addition, on the control map M3, in a range in which the absolute value of the vehicle speed V is equal to or greater than 0 and less than the second predetermined vehicle speed V ₂ , the gain P ₂ increases linearly according to the absolute value of the vehicle speed V. Specifically, on the control map M3, in a range in which the absolute value of the vehicle speed V is equal to or greater than 0 and less than the second predetermined vehicle speed V ₂ , the gain P ₂ is set in accordance with a linear function representing the relationship between the absolute value of the vehicle speed V means and gain P ₂ . In a linear function, when the absolute value of the vehicle speed V is 0, the gain P ₂ is set to the fifth predetermined value (0.5), and when the absolute value of the vehicle speed V is the second predetermined vehicle speed V ₂ , the gain P ₂ is set to the sixth setpoint (1.0). Accordingly, the axial direct coupling force calculating unit 11Ba sets the absolute value of the damping component smaller (corrects) as the absolute value of the vehicle speed V becomes smaller when the absolute value of the vehicle speed V is less than the second predetermined vehicle speed V ₂ . In addition, the axial direct coupling force calculating unit 11Ba does not correct the absolute value of the damping component based on the gain P ₂ regardless of the absolute value of the vehicle speed V when the absolute value of the vehicle speed V is equal to or greater than the second predetermined vehicle speed V ₂ .

[0023] As described above, the control parameter calculating module 11 in one embodiment of the present disclosure sets the absolute value of the damping component lower as the absolute value of the vehicle speed V becomes smaller. In this document, in a steering control device from a mechanical system in which the steering wheel 1 and the steered wheels are mechanically engaged with each other when the vehicle speed V decreases, the lateral force Fd on the tires of the steered wheels 2 decreases, and the steering force decreases. On the contrary, the control parameter calculating module 11 in one embodiment of the present disclosure sets the absolute value of the damping component lower as the absolute value of the vehicle speed V decreases, the steering force may decrease. Accordingly, the control parameter calculating module 11 in one embodiment of the present disclosure allows for a more appropriate taxiing feel.

[0024] FIG. 10 is a graph representing a control card M4.

As a method for setting the damping component for correction, for example, a method for reading the damping component for correction corresponding to the absolute value of the angular velocity dδ / dt of steering from the control map M4 can be used. As a control map M2, as an example, a map is provided in which damping components for correction corresponding to the absolute values of the angular velocity dδ / dt of steering are registered. Specifically, as illustrated in FIG. 10, a control map M4 is set for each vehicle speed V. On each control map M4, when the angular speed dδ / dt of taxiing is 0, the damping component for correction is set to the seventh predetermined value (for example, 0.0). In addition, on the control map M4, in the range in which the absolute value of the angular velocity dδ / dt of taxiing is equal to or greater than the second preset angular velocity dδ ₂ / dt of taxiing (> 0), the damping component for correction is set equal to the eighth preset value (constant value ) regardless of the absolute value of the angular velocity dδ / dt of taxiing. Additionally, on the control map M4, in the range in which the angular velocity dδ / dt of taxiing is equal to or greater than 0.0, and the absolute value of the angular velocity dδ / dt of taxiing is less than the third preset angular velocity dδ ₃ / dt of taxiing (0 <dδ ₃ / dt <dδ ₂ / dt), the damping component for correction increases linearly according to the absolute value of the angular velocity dδ / dt of taxiing. In particular, on each control card M4, in the range in which the absolute value of the angular velocity dδ / dt of steering is equal to or greater than 0 and less than the third predetermined angular velocity dδ ₃ / dt of steering, the damping component for correction is set in accordance with a linear function representing the relationship between the absolute value of the angular velocity dδ / dt of taxiing and the damping component for correction. In a linear function, when the absolute value of the angular velocity dδ / dt of taxiing is 0, the damping component for correction is set to the seventh preset value (0,0), whereas when the absolute value of the angular velocity dδ / dt of taxiing is the third preset angular velocity dδ ₃ / dt taxiing, the damping component for correction is set equal to the ninth setpoint (0 <ninth setpoint <eighth setpoint). In addition, on each control card M4, in a range in which the absolute value of the angular velocity dδ / dt of taxiing is equal to or greater than the third preset angular velocity dδ ₃ / dt of taxiing and less than the second preset angular velocity dδ ₂ / dt of taxiing, the damping component for correction linearly increases according to the absolute value of the angular velocity dδ / dt of taxiing. Specifically, on the control map M4, in a range in which the absolute value of the angular velocity dδ / dt of taxiing is equal to or greater than the third preset angular velocity dδ ₃ / dt of taxiing and less than the second predetermined angular velocity dδ ₂ / dt of taxiing, the damping component for correction is set in in accordance with a linear function representing the relationship between the absolute value of the vehicle speed V and the damping component for correction. In a linear function, when the absolute value of the angular velocity dδ / dt of taxiing is the third preset angular velocity dδ ₃ / dt of steering, the damping component for correction is set to the ninth preset value, whereas when the absolute value of the angular velocity dδ / dt of taxiing is the second preset angular taxiing speed dδ ₂ / dt, the damping component for correction is set equal to the eighth preset value. Accordingly, the axial direct coupling force calculating unit 11Ba sets the absolute value of the damping component to be corrected larger as the absolute value of the angular speed dδ / dt of steering becomes larger when the absolute value of the angular speed dδ / dt of steering is less than the second predetermined angular speed dδ ₂ / dt taxiing. In addition, the direct coupling axial force calculating unit 11Ba sets the absolute value of the damping component for correction equal to a constant value regardless of the absolute value of the angular velocity dδ / dt of taxiing, when the absolute value of the angular velocity dδ / dt of taxiing is equal to or greater than the second preset angular velocity dδ ₂ / dt taxiing.

[0025] As described above, the control parameter calculating module 11 in one embodiment of the present disclosure sums the damping component for correction, which becomes larger as the absolute value of the angular velocity dδ / dt of the steering becomes larger with the axial force T _{FF of the} straight line communication. Accordingly, the control parameter calculation module 11 in one embodiment of the present disclosure allows an increase in the initiation of the reaction force when taxiing when the absolute value of the angular velocity dδ / dt of the taxi increases at the start of the steering wheel 1. Accordingly, the control parameter calculation module 11 in one embodiment of the present disclosure of the essence allows the provision of a more appropriate sensation when taxiing.

Additionally, the control parameter calculating module 11 in one embodiment of the present disclosure sets a predetermined constant value equal to the damping component for correction when the absolute value of the angular velocity dδ / dt of taxiing is equal to or greater than the second predetermined angular velocity dδ ₂ / dt of taxiing. Therefore, when the driver turns the steering wheel 1, and the absolute value of the angular velocity dδ / dt of steering is equal to or greater than the second predetermined angular velocity dδ ₂ / dt of steering, it is possible to suppress the damping component for correction. Thus, the control parameter calculating module 11 in one embodiment of the present disclosure allows preventing non-reading of changes in the reaction force when taxiing caused by changing the damping component for correction, thereby causing a strange steering sensation in the driver.

[0026] FIG. 11 is a block diagram illustrating a configuration of an axial feedback force calculating unit 11Bb.

As shown in FIG. 11, the axial feedback force calculating unit 11Bb is configured to include the axial current calculating unit 11Bba, the mixed axial force calculating unit 11Bb, the steering angular velocity detection unit 11Bbc, the steering determining module 11Bbd, and the axial feedback force calculating unit 11Bb.

The axial current calculating unit 11Bba is configured to calculate the axial force of the steering gear (axial force of the steering gear, hereinafter, also referred to as “axial electric current”) according to the following expression (6) based on the electric current when turning, detected by turning current detection module 8B. In the following expression (6), firstly, the electric current during rotation is multiplied, the torque constant [Nm / A] for calculating the output torque of the rotary engine 8A based on the electric current during rotation, and the gear ratio of the engine for transmitting the torque of the rotary engine motor 8A. Then, in the following expression (6), the multiplication result is divided by the radius of the drive gear [m] of the rotary engine 8A, the division result is multiplied by the efficiency when the output torque of the rotary engine 8A is transmitted, and the multiplication result is calculated as the axial electric current. Then, the axial current calculating unit 11Bba outputs the calculation result to the mixed axial force calculating unit 11Bbb and the axial feedback force calculating unit 11Bbe.

Axial force of electric current = (electric current when turning * engine gear ratio * torque constant [Nm / A] / pinion radius [m]) * efficiency ... (6)

[0027] In this document, the electric current during rotation fluctuates when the steering wheel 1 rotates, the target angle θ * of rotation fluctuates, and a difference is set between the target angle θ * of rotation and the actual angle of rotation θ. In addition, the electric current during rotation also fluctuates when the steered wheels 2 are turned, the lateral force Fd on the tires is applied to the steered wheels 2, and the difference between the target steering angle θ * and the actual turning angle θ is set. Additionally, the electric current during rotation also fluctuates when disturbances of the road surface affect the steered wheels 2 by means of bumps and the like. of the road surface, a lateral force Fd on the tires is applied to the steered wheels 2, and a difference between the target rotation angle θ * and the actual rotation angle θ is set. Therefore, the axial feedback force calculating unit 11Bb allows the calculation of the axial force of the steering gear rack (axial electric current), which reflects the influence of the lateral force Fd on the tires, which should be applied to the steered wheels 2, based on the electric current when turning. In this document, an axial electric current is generated while the difference between the target rotation angle θ * and the actual rotation angle θ is specified. For this reason, a phase advance in the axial force of the electric current is ensured in comparison with the actual axial force of the steering rack or the axial force of the transverse G, as illustrated in FIG. 12.

[0028] The mixed axial force calculating unit 11Bbb calculates the axial force of the steering gear (hereinafter, also referred to as the "axial transverse force G") according to the following expression (7) based on the lateral acceleration Gy detected by the transverse G sensor 6. In the following expression (7), firstly, the front wheel load and lateral acceleration Gy are multiplied, and the multiplication result is calculated as the axial force (axial force) applied to the steered wheels 2. Then, in the following expression (7), taka calculated axial force that must be applied to the steerable wheels 2 and a constant (hereinafter in this document, also called "traction coefficient") according to the thrust angle or suspension are multiplied, and the multiplication result is computed as the axial force transverse G.

Axial transverse force G = axial force applied to the steered wheels 2 * traction coefficient ... (7).

Axial force applied to steered wheels 2 = front wheel load * lateral acceleration Gy.

[0029] Here, the lateral acceleration Gy is formed when the steered wheels 2 are turned, the lateral force Fd on the tires is applied to the steered wheels 2, and the vehicle A rotates. Accordingly, the mixed axial force calculation module 11Bbb allows the calculation of the axial force of the steering gear (axial lateral force G), which reflects the influence of the lateral force Fd on the tires, which must be applied to the steered wheels 2, based on the lateral acceleration Gy. In this document, since the transverse G sensor 6 is located on the spring (vehicle body), the detection of the lateral acceleration Gy is delayed. Therefore, as illustrated in FIG. 12, there is a phase delay in the axial force of the transverse G compared to the actual axial force of the steering gear.

It should be noted that in one embodiment of the present disclosure, an example of using transverse acceleration Gy detected by transverse G sensor 6 when an axial force of transverse G is calculated is described. However, a different configuration may be used. For example, a configuration may be used in which the yaw rate γ detected by the yaw rate sensor 7 is multiplied by the vehicle speed V detected by the vehicle speed sensor 5, and the multiplication result γ * V is used instead of the lateral acceleration Gy.

[0030] In addition, the mixed axial force calculation module 11Bbb calculates the axial force of the steering gear rack (hereinafter, also referred to as "axial yaw rate axial force") according to expression (8) based on the vehicle speed V detected by the sensor 5 of the vehicle speed and the yaw rate γ detected by the yaw rate sensor 7. In the following expression (8), firstly, the load on the front wheels, the vehicle speed V and the yaw rate γ are multiplied, and the multiplication result is calculated as the axial force applied to the steered wheels 2. Then, in the following expression (8), such a calculated axial force, which must be applied to the steered wheels 2, and the traction coefficient are multiplied, and the multiplication result is calculated as the axial force of the angular velocity of yaw.

Axial force of the angular velocity of yaw = axial force applied to the steered wheels 2 * traction coefficient ... (8)

Axial force applied to steered wheels 2 = front wheel load * vehicle speed V * yaw angular speed γ.

[0031] Here, the yaw rate γ is generated when the steer wheels 2 are turned, the lateral force Fd on the tires is applied to the steered wheels 2, and the vehicle A is turning. Thus, the mixed axial force calculation module 11Bbb allows the calculation of the axial force of the steering gear (axial yaw rate force, which reflects the influence of the lateral force Fd on the tires, which should be applied to the steered wheels 2, based on the yaw rate. Here, since the yaw rate sensor 7 is located on the spring (vehicle body), the detection of the yaw rate γ is delayed, therefore, in the axial force depending on the speed relative to the vertical cial axis, as illustrated in FIG. 12, provided by the delay in phase as compared with an actual axial force of the steering rack.

[0032] Furthermore, the mixed axial force calculating unit 11Bbb reads the axial electric current from the axial current calculating unit 11Bba. Then, the mixed axial force calculation unit 11Bbb calculates the axial force T _{BR of the} steering rack (hereinafter, also referred to as “mixed axial force”) according to the following expression (9) based on the axial electric current that is read out, the axial transverse force G , which is calculated, and the axial force of the angular velocity of yaw. In the following expression (9), the axial force of the transverse G is multiplied by the distribution coefficient K1, the axial force of the electric current is multiplied by the distribution coefficient K2, the axial force depending on the angular yaw rate is multiplied by the distribution coefficient K3, and the sum of these multiplication results is calculated as the mixed axial force T _BR . In other words, the mixed axial force T _{BR is} calculated based on the value obtained by multiplying the axial force of the transverse G by the distribution coefficient K1, the value obtained by multiplying the axial force of the electric current by the distribution coefficient K2, and the value obtained by multiplying the axial force of the angular yaw rate by the distribution coefficient K3. Then, the mixed axial force calculation unit 11Bbb outputs the calculation result to the taxiing determination unit 11Bbd and the axial feedback force calculation unit 11Bbe. Here, the mixed axial force T _BR takes a positive value for the axial force to turn the steered wheels 2 to the right, and has a negative value for the axial force to turn the steered wheels 2 to the left.

T _BR = axial transverse force G * K1 + axial electric current strength * K2 + axial yaw rate * K3 ... (9)

[0033] Here, the distribution coefficients K1, K2 and K3 are the distribution coefficients of the axial transverse force G, axial electric current and axial yaw rate. The ratio of the absolute values between the distribution coefficients K1, K2 and K3 is configured to satisfy K1>K2> K3. In other words, the distribution coefficients are set in decreasing order of the axial force of the transverse G, the axial force of the electric current and the axial force of the angular velocity of yaw. For example, the distribution coefficients K1, K2, and K3, respectively, are set in such a way that K1 = 0.6, K2 = 0.3, and K3 = 0.1. Therefore, the mixed axial force calculation unit 11Bbb calculates the axial force of the steering rack, which reflects the influence of the lateral force Fd on the tires to be applied to the steered wheels 2, as the mixed axial force T _BR .

[0034] FIG. 13 is a graph representing the mixed axial force T _BR and the actual axial force of the steering rack.

Thus, the mixed axial force calculation module 11Bbb in one embodiment of the present disclosure calculates the mixed axial force T _BR based on the value obtained by multiplying the axial electric current by the distribution coefficient K2 and the value obtained by multiplying the axial transverse force G by the coefficient K1 distribution. Here, as illustrated in FIG. 12, there is a phase delay in the axial force of the transverse G compared to the actual axial force of the steering gear. In addition, phase advance in the axial force of the electric current is ensured in comparison with the actual axial force of the steering rack. Accordingly, the mixed axial force calculation module 11Bbb in one embodiment of the present disclosure sums the axial electric current with the axial transverse force G, so that the phase delay caused by the axial transverse G force can be compensated, as illustrated in FIG. 13, and a more appropriate mixed axial force T _BR can be calculated. Therefore, the control parameter calculating module 11 in one embodiment of the present disclosure drives the motor 9A to generate a reaction force based on the mixed axial force T _BR , so that a more appropriate taxiing force can be applied.

[0035] In addition, the mixed axial force calculation module 11Bbb in one embodiment of the present disclosure calculates the mixed axial force T _BR based on the value obtained by multiplying the axial electric current by the distribution coefficient K2 and the value obtained by multiplying the axial transverse force G by the distribution coefficient K1. Here, in the vehicle A, when road surface disturbances act on the steered wheels 2 by means of bumps or the like the surface of the road, and the lateral force Fd on the tires is applied to the steered wheels 2, a difference between the target steering angle θ * and the actual steering angle θ is set. Therefore, the mixed axial force calculation module 11Bbb in one embodiment of the present disclosure sums the axial electric current with the axial transverse force G, so that the influence of the disturbances of the road surface that affects the steered wheels 2 can be reflected in the mixed axial force T _BR , and a more appropriate mixed axial force T _BR can be calculated.

Therefore, the control parameter calculating module 11 in one embodiment of the present disclosure drives the motor 9A to generate a reaction force based on the mixed axial force T _BR , so that a more appropriate taxiing force can be applied.

In addition, the mixed axial force calculation module 11Bbb in one embodiment of the present disclosure sets the axial force distribution coefficient K1 of the transverse G so that it exceeds the axial electric current distribution coefficient K2. Therefore, the mixed axial force calculation module 11Bbb in one embodiment of the present disclosure allows for a reduction in the axial force distribution coefficient of the electric current, and even if the estimated accuracy of the axial electric force is deteriorated by the inertia or friction of the rotary motor 8A, such a deterioration in the estimated accuracy of the mixed axial T _BR forces can be suppressed. Therefore, the control parameter calculating module 11 in one embodiment of the present disclosure drives the motor 9A to generate a reaction force based on the mixed axial force T _BR , so that a more appropriate taxiing force can be applied.

[0036] In addition, the mixed axial force calculation unit 11Bbb in one embodiment of the present disclosure calculates the axial feedback force T _FB based on the value obtained by multiplying the axial electric current by the distribution coefficient K2, the value obtained by multiplying the axial transverse force G by the distribution coefficient K1, and the value obtained by multiplying the axial force of the angular yaw rate by the distribution coefficient K3. Here, for example, when the vehicle A enters a skid state, the electric current when turning and the increase in lateral acceleration Gy. Therefore, the detection result of the transverse G sensor 6 and the detection result of the rotational current detection module 8B take maximum values (saturated values). On the contrary, although the angular velocity γ of yaw also increases, the magnitude of the increase in the angular velocity γ of yaw is less than the magnitudes of the increase in electric current during rotation and the transverse acceleration Gy. Therefore, the detection result of the yaw rate sensor 7 does not reach the maximum value (saturated value). Therefore, the detection result of the yaw rate sensor 7 varies depending on the degree of skidding of vehicle A. Accordingly, the mixed axial force T _BR may vary depending on the degree of skidding of vehicle A. As a result, control parameter calculation module 11 in one embodiment the implementation of the present disclosure drives the motor 9A to generate a reaction force based on the mixed axial force T _BR , so that more can be applied proper reaction power when taxiing.

The steering angular velocity detection module 11Bbc calculates the steering angular velocity dδ / dt of the steering wheel 1 based on the steering angle δ detected by the steering angle sensor 3. Then, the steering angular velocity detection unit 11Bbc outputs the calculation result to the mixed axial force calculation unit 11Bbb and the taxiing determination unit 11Bbd. Here, the angular velocity dδ / dt of the taxi is set so that it takes a positive value of the angular velocity when the steering wheel 1 rotates clockwise, and takes a negative value of the angular velocity when the steering wheel 1 rotates counterclockwise.

[0037] The steering determination module 11Bbd determines that the driver further turns the steering wheel 1 or returns the steering wheel 1 based on the mixed axial force T _BR calculated by the mixed axial force calculation module 11Bbb and the angular steering speed dδ / dt detected by the 11Bbc module detect angular taxiing speed. As an additional turning operation, for example, the steering wheel 1 (steering angle δ when steering) is controlled in a direction further from the neutral position. In addition, as a return operation, for example, the steering wheel 1 (steering angle δ when steering) is controlled in a direction closer to the neutral position. Specifically, the taxiing determination unit 11Bbd determines that an additional rotation operation is performed, and sets the variable K4 to 1.0 when the mixed axial force T _BR is a positive value and the angular velocity dδ / dt of the taxi is a positive value, or when the mixed axial force T _BR is a negative value, and the angular velocity dδ / dt of taxiing is a negative value. Variable K4 is a flag representing which of the secondary rotation or return operation is performed. The variable K4 is set in such a way that when an additional steering wheel 1 operation is performed, the variable K4 is set to 1.0, while when the return operation is performed, the variable K4 is set to 0.0. Additionally, the steering determination module 11Bbd determines that no additional steering 1 turn operation is performed, and sets the variable K4 to 0 when the mixed axial force T _BR is a positive value and the angular speed dδ / dt of the steering is a negative value, or when the mixed axial the force T _BR is a negative value, and the angular velocity dδ / dt of taxiing is a positive value. Then, the taxiing determination unit 11Bbd outputs the variable K4, which is set, to the axial feedback force calculation unit 11Bbe.

[0038] The axial feedback force calculating section 11Bbe reads the axial electric current, the mixed axial force T _BR , the steering angular velocity dδ / dt and the variable K4 from the axial current calculating section 11Bba, the mixed axial force calculating section 11Bbb, the detection section 11Bbc steering angular velocity and taxiing determination module 11Bbd, respectively. Then, the axial feedback force calculating unit 11Bbe calculates the steering axle axial force (hereinafter, axial feedback force T _FB ) according to the following expression (10) based on the axial electric current strength, mixed axial force T _BR , angular taxiing speed dδ / dt and variable K4, which are read. Then, the axial feedback force calculating unit 11Bbe outputs the calculation result to the axial feedback force correction unit 11Bf.

Axial feedback force T _FB = axial electric current * GB + mixed axial force T _BR * (1-GB) ... (10)

[0039] Nevertheless, GB is a numerical value representing the coefficient GB axial distribution of electrical current and the coefficient (1-GB) mixed distribution of the axial force T _BR (in hereinafter, called "partition coefficient"). Accordingly, the axial feedback force calculation calculation unit 11Bbe calculates the axial feedback force T _FB by adding the axial electric current strength and the mixed axial force T _BR with the coefficient GB: (1-GB) based on the distribution coefficient GB.

Here, as a method for setting the distribution coefficient GB, for example, a method for setting the distribution coefficient GB by the distribution coefficient setting unit 11Bbf based on the determination result output from the taxiing determination unit 11Bbd can be used. The distribution coefficient setting module 11Bbf reads the taxiing angular velocity dδ / dt and the variable K4 from the taxiing determination module 11Bbd. Then, the distribution coefficient setting module 11Bbf calculates a distribution coefficient GB according to the following expression (11) based on the angular taxiing speed dδ / dt and the variable K4 that are read.

GB = K4 * K5 ... (11)

[0040] However, K5 is a numerical value representing an axial current distribution coefficient GB and a mixed axial force distribution coefficient T _BR when K4 is 1.0, i.e. in the operation of the additional steering wheel 1. Accordingly, the axial feedback force calculation module 11Bbe sums the axial electric current and the mixed axial force T _BR based on the variable K5 with the coefficient K5: (1-K5), in the operation of the additional steering 1, so that calculate the axial force T _FB feedback. It should be noted that when K4 is 0.0, i.e. during the steering wheel return operation 1, the mixed axial force T _BR is set equal to the axial feedback force T _FB regardless of the variable K5.

Here, as a method of setting the variable K5, for example, a method of reading the variable K5 corresponding to the angular steering speed dδ / dt from the control map M5 can be used. As a control map M5, as an example, a map is provided in which the variables K5 corresponding to the steering angular velocities dδ / dt are registered.

[0041] FIG. 14 is a graph representing a control card M5.

As illustrated in FIG. 14, on the control map M5, in a range in which the absolute value of the angular velocity dδ / dt of steering is equal to or greater than 0 and less than the fourth predetermined angular velocity dδ ₄ / dt of steering (> 0), the variable K5 is set equal to the tenth preset value (for example, 1,0) regardless of the absolute value of the angular velocity dδ / dt taxiing. In addition, on the control map M5, in the range in which the absolute value of the angular velocity dδ / dt of taxiing is equal to or greater than the fifth preset angular velocity dδ ₅ / dt of taxiing (> dδ ₄ / dt), the variable K5 is set equal to the eleventh preset value (< tenth preset value, for example, 0.0) regardless of the absolute value of the angular velocity dδ / dt of taxiing. Additionally, on the control map M5, in a range in which the absolute value of the angular velocity dδ / dt of taxiing is equal to or greater than the fourth preset angular velocity dδ ₄ / dt of taxiing and less than the fifth preset angular velocity dδ ₅ / dt of taxiing, the variable K5 linearly decreases according to the absolute value of the angular velocity dδ / dt of taxiing. Specifically, on the control map M5, in the range in which the absolute value of the angular velocity dδ / dt of taxiing is equal to or greater than the fourth preset angular velocity dδ ₄ / dt of taxiing and less than the fifth preset angular velocity dδ ₅ / dt of taxiing, the variable K5 is set in accordance with a linear function representing the relationship between the absolute value of the angular velocity dδ / dt of taxiing and the variable K5. In a linear function, if the absolute value of the angular velocity dδ / dt of taxiing is the fourth preset angular speed dδ ₄ / dt of taxiing, the variable K5 is set equal to the tenth preset value (1,0), if the absolute value of the angular velocity dδ / dt of taxiing makes up the fifth preset angular velocity dδ ₅ / dt of taxiing, the variable K5 is set equal to the eleventh preset value (0,0). Accordingly, the distribution coefficient setting module 11Bbf sets the distribution coefficient GB to 1.0 when the variable K4 is 1.0 (during an additional rotation operation), and when the absolute value of the angular steering speed dδ / dt is less than the fourth predetermined angular steering speed dδ ₄ / dt (during taxiing operation at low speed). Then, the axial feedback force calculation unit 11Bbe sets the axial electric current strength to the axial feedback force T _FB . In addition, the distribution coefficient setting module 11Bbf sets the distribution coefficient GB to 0.0 if the variable K4 is 1.0 (during an additional rotation operation) and the absolute value of the angular velocity dδ / dt of the taxi exceeds the fifth preset angular velocity dδ ₅ / dt taxiing (during taxiing operations at high speed). Accordingly, the axial feedback force calculation unit 11Bbe sets the mixed axial force T _BR equal to the axial feedback force T _FB . Additionally, the distribution coefficient setting module 11Bbf sets the variable K5 to the distribution coefficient GB if the variable K4 is 1.0 (during an additional rotation operation) and the absolute value of the angular velocity dδ / dt of taxiing is equal to or greater than the fourth preset angular velocity dδ ₄ / taxiing dt and less than the fifth preset angular speed dδ ₅ / dt taxiing (during taxiing operation at medium speed). Accordingly, the axial feedback force calculating unit 11Bbe sets the value to the axial feedback force T _FB , the value obtained by summing the value obtained by multiplying the axial electric current by the variable K5 and the value obtained by multiplying the mixed axial force T _BR by (1-K5). On the other hand, the distribution coefficient setting module 11Bbf sets 0.0 as the distribution coefficient GB when the variable K4 is 0.0 (in the return operation), irrespective of the angular steering speed dδ / dt. Then, the axial feedback force calculation unit 11Bbe sets the mixed axial force T _BR equal to the axial feedback force T _FB .

[0042] Thus, when the steering 1 return operation is performed, the axial feedback force calculating unit 11Bbe in one embodiment of the present disclosure sets the axial electric current force to the axial feedback force T _FB if the absolute value of the fourth angular velocity dδ / dt taxiing is less than the fourth predetermined angular velocity dδ ₄ / dt taxiing. In the mechanical type of the steering control device in which the steering wheel 1 and the steered wheels 2 are mechanically engaged with each other, the steering force in order to return the steering wheel 1 to a neutral position is generated by the lateral force Fd on the tires corresponding to the rotation of the steered wheels 2, and friction, during the operation of the additional steering wheel turn 1. In addition, in the module 11Bbe for calculating the axial feedback force in one embodiment of the present disclosure, the axial electric current is equal to the sums the adjusted lateral force Fd on the tires and friction during an additional steering 1 turn operation. Therefore, the control parameter calculation module 11 in one embodiment of the present disclosure sets the axial electric current strength to the axial feedback force T _FB , so that a reaction force can be applied when taxiing in order to return the steering wheel 1 to a neutral position, similar to the mechanical type of the steering control device. Accordingly, the control parameter calculating module 11 in one embodiment of the present disclosure allows the application of a more appropriate reaction force when taxiing during an additional turn of the steering wheel 1.

Incidentally, the coefficient of friction corresponding to the rotation of the steered wheels 2 is not included in the mixed axial force T _BR . Therefore, for example, if the method of setting the mixed axial force T _BR equal to the axial feedback force T _{FB is} used during an additional steering 1 turn operation, there is a possibility that the steering sensation includes an uncomfortable sensation.

[0043] In addition, when the steering 1 return operation is performed, the axial feedback force calculating unit 11Bbe in one embodiment of the present disclosure defines a mixed axial force T _BR in which the axial electric current and the axial transverse force G are distributed with a predetermined distribution coefficient equal to the axial feedback force T _FB regardless of the absolute value of the absolute value of the angular velocity dδ / dt taxiing. Here, in the mechanical type of the steering control device in which the steering wheel 1 and the steered wheels 2 are mechanically engaged with each other during the steering 1 return operation, the steering force in order to return the steering wheel 1 to the neutral position is generated by the lateral force Fd on the tires, corresponding to the rotation of the steered wheels 2. Thus, in the mechanical type of the steering control device, during the steering wheel 1 return operation, the driver reduces the holding force to hold the steering wheel 1 and makes the steering wheel 1 slide smoothly Adoni to return the steering wheel 1 in the neutral position and return the steerable wheels 2 in a neutral position. In contrast, according to the axial feedback force calculation calculation unit 11Bbe in one embodiment of the present disclosure, the mixed axial force T _BR is set equal to the axial feedback force T _FB . Therefore, even if the electric current during rotation decreases, and the axial force of the electric current decreases, it is possible to suppress the reaction force during taxiing in order to return the steering wheel 1 to the neutral position. Accordingly, the axial feedback force calculating unit 11Bbe in one embodiment of the present disclosure returns steering wheel 1 to a neutral position, similar to the mechanical type of steering control device, when the driver reduces the holding force to hold steering wheel 1 and makes steering wheel 1 slip smoothly in the palm of your hand. Accordingly, the control parameter calculating module 11 in one embodiment of the present disclosure allows the application of a more appropriate reaction force when taxiing during the steering 1 return operation.

[0044] Further, when it is determined that the additional steering 1 return operation is performed, and the absolute value of the steering angular velocity dδ / dt is equal to or greater than the fourth predetermined steering angular velocity dδ ₄ / dt, the axial feedback force calculation module 11Bbe in one embodiment of the implementation of the present disclosure, mixes the axial force of the electric current and the mixed axial force T _BR to set the axial feedback force T _FB , and in addition to set the distribution coefficient of the axial force of the electric current as the absolute value of the angular velocity dδ / dt of taxiing becomes smaller. Accordingly, for example, when the steering angle δ during steering moves to a neutral position, and the additional steering 1 return operation is continuously performed, when the steering 1 returns, the axial feedback force calculation unit 11Bbe in one embodiment of the present disclosure allows gradual switching of the axial force T _FB feedback from the mixed axial force T _BR to the axial force of the electric current as the absolute value of the angular velocity dδ / dt of steering gradually decreases when operating walkie-talkie extra return. Accordingly, the control parameter calculating module 11 in one embodiment of the present disclosure allows the application of a more appropriate taxiing force.

[0045] Returning to FIG. 3, the final axial force calculation module 11Bc reads the steering angle δ, the vehicle speed V, the lateral acceleration Gy, the direct axial force T _FF and the axial feedback force T _FB from the steering angle sensor 3, the vehicle speed sensor 5 , transverse G sensor 6, axial direct axial force calculating unit 11Ba and axial feedback force correcting unit 11Bf, respectively. Then, the final axial force calculating unit 11Bc calculates an angular steering speed dδ / dt of the steering wheel 1 based on the steering angle δ that was read. Then, the final axial force calculation unit 11Bc calculates the axial force of the steering rack (hereinafter referred to as the "final axial force") according to the following expression (12) based on the steering angle δ, the speed V of the vehicle, the lateral acceleration Gy, the axial force T _{FF of the} direct coupling and the axial force T _{FB of the} feedback that are read, and the angular velocity dδ / dt of the steering, which is calculated. Then, the final axial force calculation unit 11Bc outputs the result of the calculation to the steering force and axial force conversion unit 11Bd.

Final axial force = axial force T _FF direct coupling * GF + axial force T _FB feedback * (1-GF) ... (12)

[0046] Here, GF is a numerical value (hereinafter referred to as the "distribution coefficient") to represent the axial force distribution coefficient T _FF GF of the forward coupling and the distribution coefficient (1-GF) of the axial force distribution T _{FB of the} feedback . Accordingly, the finite axial force calculating unit 11Bc sums the axial direct coupling force T _FF and the axial feedback force T _FB with the coefficient GF: (1-GF) based on the distribution coefficient GF so as to calculate the final axial force.

Thus, the final axial force calculation unit 11Bc in one embodiment of the present disclosure calculates the final axial force based on the feedback axial force T _FB and the direct coupling axial force T _FF . Here, the axial feedback force T _FB varies depending on a change in the road surface or a change in the state of the vehicle, since the influence of the lateral force Fd on the tires applied to the steered wheels 2 is reflected in the axial feedback force T _FB . On the contrary, since the influence of the lateral force Fd on the tires does not affect the axial force T _{FF of the} direct coupling, the axial force T _{FF of the} direct coupling smoothly changes regardless of the change, etc. road surface. Accordingly, the final axial force calculating unit 11Bc calculates the final axial force based not only on the axial feedback force T _FB , but also the direct coupling axial force T _FF , so that a more appropriate final axial force can be calculated.

[0047] The final axial force calculation unit 11Bc is configured to include distribution coefficient calculation unit 11Bca. The distribution coefficient calculation module 11Bca is configured to set the distribution coefficient GF based _{on the} distribution coefficient GF ₁ based on the difference in axial forces, the distribution coefficient GF ₂ based on the lateral acceleration Gy, the distribution coefficient GF ₃ based on the vehicle speed V and the steering angle δ and a distribution coefficient GF ₄ based on the angular rate dδ / dt of taxiing. As the difference in axial forces, for example, the difference between the axial direct coupling force T _FF and the axial feedback force T _FB can be used. In particular, the axial force difference is defined as a result of subtraction obtained by subtracting the axial feedback force T _FB from the axial direct coupling force T _FF . In addition, as a method of setting the distribution coefficient GF, for example, a method of multiplying a smaller value from the distribution coefficient GF ₁ based on the difference in axial forces or the distribution coefficient GF ₂ based on the lateral acceleration Gy, the distribution coefficient GF ₃ based on the vehicle speed V can be used. and the steering angle δ and the distribution coefficient GF ₄ based on the angular rate dδ / dt of the steering and then setting the multiplication result as the distribution coefficient GF.

[0048] FIG. 15 is a graph representing a control card M6.

As a method for setting the distribution coefficient GF ₁ , for example, a method for reading the distribution coefficient GF ₁ corresponding to the absolute value of the axial force difference from the control card M6 can be used. As a control card M6, for example, a card is provided in which distribution coefficients GF ₁ are recorded corresponding to the absolute values of the axial force difference. Specifically, as illustrated in FIG. 15, on the control map M6, in a range in which the absolute value of the axial force difference is equal to or greater than 0 and less than the first predetermined axial force difference Z1 (> 0), the distribution coefficient GF ₁ is set to the twelfth predetermined value (for example, 1.0) regardless of the absolute value of the difference in axial forces. As a first predetermined axial force difference Z1, for example, an axial force difference can be used, by which the estimated axial force accuracy T _{FF of the} direct coupling starts to deteriorate. In addition, on the control map M6, in a range in which the absolute value of the axial force difference is equal to or greater than the second predetermined axial force difference Z2 (> Z1), for example, the distribution coefficient GF ₁ is set equal to the thirteenth predetermined value (<twelfth predetermined value, for example , 0,0) regardless of the absolute value of the difference in axial forces. As a second predetermined axial force difference Z2, for example, an axial force difference can be used by which the estimated axial force accuracy T _{FF of the} direct coupling is set lower than the estimated accuracy of the axial force T _{FB of the} feedback. Further, on the control map M6, in a range in which the absolute value of the axial force difference is equal to or greater than the first predetermined axial force difference Z1 and less than the second predetermined axial force difference Z2, the distribution coefficient GF ₁ linearly decreases according to the absolute value of the axial force difference. Specifically, on the control map M6, in a range in which the absolute value of the axial force difference is equal to or greater than the first predetermined axial force difference Z1 and less than the second predetermined axial force difference Z2, the distribution coefficient GF ₁ is set in accordance with the linear function so that it represents the relationship between the absolute value of the difference between the axial forces and the distribution coefficient GF ₁ . In a linear function, if the absolute value of the difference between the axial forces is the first specified difference Z1 of the axial forces, the distribution coefficient GF ₁ is set equal to the twelfth set value (1.0), whereas if the absolute value of the difference between the axial forces is the second specified difference Z2 axial forces, the distribution coefficient GF ₁ is set equal to the thirteenth predetermined value (0,0).

[0049] Thus, if the first absolute value of the axial force difference is equal to or greater than the first predetermined axial force difference Z1, the finite axial force calculation unit 11Bc in one embodiment of the present disclosure sets the distribution coefficient GF ₁ (axial force distribution coefficient GF T Direct coupling _FF ) is smaller than the coefficient for the case in which the absolute value of the axial force difference is less than the first specified axial force difference Z1. Thus, for example, when the road surface μ decreases, the estimated accuracy of the axial force T _{FF of the} direct coupling deteriorates, and the difference in axial forces increases, the final axial force calculation module 11Bc in one embodiment of the present disclosure allows an increase in the axial distribution coefficient (1-GF) force T _FB feedback. Therefore, the final axial force calculating unit 11Bc in one embodiment of the present disclosure allows the application of a more appropriate taxiing force.

[0050] FIG. 16 is a graph representing a control card M7.

Here, as a method for setting the distribution coefficient GF ₂ , for example, a method for reading the distribution coefficient GF ₂ corresponding to the absolute value of the lateral acceleration Gy from the control card M7 can be used. As a control card M7, for example, a card is provided in which the distribution coefficients GF ₂ corresponding to the absolute values of the lateral acceleration Gy are registered. Specifically, as illustrated in FIG. 16, on the control map M7, in a range in which the absolute value of the lateral acceleration Gy ₁ is equal to or greater than 0 and less than the first predetermined lateral acceleration Gy ₁ (> 0), the distribution coefficient GF ₂ is set to the fourteenth predetermined value (for example, 1.0 ) regardless of the absolute value of the transverse acceleration Gy. As the first predetermined lateral acceleration Gy ₁ , for example, lateral acceleration Gy can be used, by which the estimated axial axial force T _FF starts to deteriorate. In addition, on the control map M7, in a range in which the absolute value of the lateral acceleration Gy is equal to or greater than the second predetermined lateral acceleration Gy ₂ (> Gy ₁ ), the distribution coefficient GF ₂ is set equal to the fifteenth predetermined value (<fourteenth predetermined value, for example, 0,0) regardless of the absolute value of the transverse acceleration Gy. As the second predetermined lateral acceleration Gy ₂ , for example, lateral acceleration Gy can be used by which the estimated axial force accuracy T _{FF of the} direct coupling is set lower than the estimated accuracy of the axial force T _{FB of the} feedback. Further, on the control map M7, in a range in which the absolute value of the lateral acceleration Gy ₁ is equal to or greater than the first lateral acceleration Gy and less than the second predetermined lateral acceleration Gy ₂ , the distribution coefficient GF ₂ linearly decreases according to the absolute value of the lateral acceleration Gy. Specifically, on the control map M7, in a range in which the absolute value of the lateral acceleration Gy is equal to or greater than the first predetermined lateral acceleration Gy ₁ and less than the second predetermined lateral acceleration Gy ₂ , the distribution coefficient GF ₂ is set in accordance with a linear function representing the relationship between the absolute the lateral acceleration value Gy and the distribution coefficient GF ₂ . In the linear function if the absolute value of the lateral acceleration Gy is a first predetermined lateral acceleration Gy _1, the distribution coefficient of GF ₃ is set to a fourteenth predetermined value (1.0), and if the absolute value of the lateral acceleration Gy is a second predetermined transverse acceleration Gy ₂ , the distribution coefficient GF ₃ is set to the fifteenth predetermined value (0.0).

[0051] Thus, in the event that the absolute value of the lateral acceleration Gy is equal to or greater than the first predetermined lateral acceleration Gy ₁ , the finite axial force calculating unit 11Bc in one embodiment of the present disclosure sets the distribution coefficient GF ₂ (axial force distribution coefficient GF T _FF direct coupling) smaller than the distribution coefficient for the case in which the absolute value of the transverse acceleration Gy _{1 is} less than the first transverse acceleration Gy. Accordingly, for example, when the lateral acceleration Gy is increased, and the estimated axial force axial force T _FF decreases, the finite axial force calculator 11Bc in one embodiment of the present disclosure allows an increase in the axial force distribution coefficient T _{FB of the} feedback coefficient T _FB . Therefore, the final axial force calculating unit 11Bc in one embodiment of the present disclosure allows the application of a more appropriate taxiing force.

[0052] FIG. 17A and FIG. 17B are graphs representing control cards M8a and M8b.

Here, as a method of setting the distribution coefficient GF ₃ , for example, a method of reading the distribution coefficients GF _3a and GF _3b corresponding to the absolute value of the vehicle speed V and the absolute value of the steering angle δ from the steering map M8a and M8b can be used, multiplying the coefficients GF _3a and GF _{3b of the} distribution that are read, and setting the multiplication result as the distribution coefficient GF ₃ . As a control card M8a, for example, a card is provided in which distribution coefficients GF ₃ corresponding to the absolute values of the vehicle speed V are registered. Specifically, as illustrated in FIG. 17A, on the control card M8a, in a range in which the absolute value of the vehicle speed V is equal to or greater than 0 and less than the third predetermined vehicle speed V3, the distribution coefficient GF _3a is set equal to the sixteenth predetermined value (for example, 0.5) regardless of the absolute vehicle speed V. As the third predetermined vehicle speed V3, for example, vehicle speed V can be used, by which a non-linearity of the tire property occurs due to a low speed for the vehicle speed V (non-linearity of the lateral force Fd on the tires relative to the tire slip angle), and the estimated accuracy starts to deteriorate axial force T _FF direct coupling. In addition, on the control card M8a, the absolute value of the vehicle speed V is equal to or greater than the fourth predetermined vehicle speed V ₄ (> V ₃ ), the distribution coefficient GF _3a is set equal to the seventeenth predetermined value (> sixteenth predetermined value, for example, 1.0 ) regardless of the absolute value of the vehicle speed V. As the fourth predetermined vehicle speed V ₄ , for example, a vehicle speed V can be used by which the estimated axial axial force T _{FF is} improved to a greater extent than the estimated axial axial force T _FB accuracy. Further, on the control card M8a, in a range in which the absolute value of the vehicle speed V is equal to or greater than the third predetermined vehicle speed V3 and less than the fourth predetermined vehicle speed V ₄ , the distribution coefficient GF _3a is linearly increased according to the absolute value of the vehicle speed V . Specifically, on the control card M8a, in a range in which the absolute value of the vehicle speed V is equal to or greater than the third predetermined vehicle speed V3 and less than the fourth predetermined vehicle speed V ₄ , the distribution coefficient GF _3a is set in accordance with a linear function representing the relationship between the vehicle speed V and the distribution coefficient GF _3a . In a linear function, if the absolute value of the vehicle speed V is the third preset vehicle speed V3, the distribution coefficient GF _3a is set to the sixteenth preset value (0.5), and if the vehicle speed V is the fourth preset speed V ₄ of the vehicle, the distribution coefficient GF _3a is set to a seventeenth predetermined value (1.0).

[0053] Thus, if the absolute value of the vehicle speed V is less than the fourth predetermined vehicle speed V ₄ , the final axial force calculating unit 11Bc in one embodiment of the present disclosure sets a distribution coefficient GF _3a (axial force distribution coefficient GF T _FF direct communication) less than the distribution coefficient for the case in which the absolute value of the vehicle speed V is equal to or greater than the fourth predetermined vehicle speed V ₄ . Therefore, the final axial force calculating unit 11Bc in one embodiment of the present disclosure allows for an increase in the coefficient of distribution (1-GF) of the axial force distribution T _{FB of the} feedback when, for example, the vehicle speed V decreases and the estimated axial force accuracy T _{FF of the} direct coupling worsens. Therefore, the final axial force calculating unit 11Bc in one embodiment of the present disclosure allows the application of a more appropriate taxiing force.

[0054] In addition, as a control card M8b, for example, a card is provided in which distribution coefficients GF _3b are recorded corresponding to the absolute values of the steering angle δ. Specifically, as illustrated in FIG. 17B, on the control map M8b, in a range in which the absolute value of the steering angle δ when taxiing is equal to or greater than 0 and less than the first predetermined steering angle δ when steering (> 0), the distribution coefficient GF _3b is set to be an eighteenth predetermined value (e.g., 1 , 0) regardless of the absolute value of the angle of rotation δ when taxiing. As the first predetermined steering angle δ1 when taxiing, for example, the steering angle δ when taxiing, by which the estimated accuracy of the axial direct coupling force T _FF starts to deteriorate, can be used. In addition, on the control map M8b, in a range in which the absolute value of the steering angle δ when taxiing is equal to or greater than the second predetermined steering angle δ when steering (> δ1), the distribution coefficient GF _3b is set equal to the nineteenth predetermined value (<eighteenth preset value, for example, 0.6) regardless of the absolute value of the angle of rotation δ when taxiing.

As the second predetermined steering angle δ2 when taxiing, for example, the steering angle δ when taxiing, by which the estimated accuracy of the axial direct force T _{FF of the} direct coupling, is worse than the estimated accuracy of the axial force T _{FB of the} feedback, can be used. Further, on the control map M8b, in a range in which the absolute value of the steering angle δ when taxiing is equal to or greater than the first predetermined steering angle δ1 when taxiing and less than the second predetermined steering angle δ2 when taxiing, the distribution coefficient GF _3b linearly decreases according to the absolute value of the angle δ turning when taxiing. Specifically, on the control map M8b, in a range in which the absolute value of the steering angle δ when taxiing is equal to or greater than the first predetermined steering angle δ1 when taxiing and less than the second predetermined steering angle δ2 when taxiing, the distribution coefficient GF _3b is set in accordance with a linear function, representing the relationship between the absolute value of the steering angle δ when taxiing and the distribution coefficient GF _3b . In a linear function, if the absolute value of the steering angle δ during taxiing is the first predetermined steering angle δ1 when taxiing, the distribution coefficient GF _3b is set equal to the eighteenth specified value (1.0), and if the absolute value of the steering angle δ makes the second predetermined steering angle δ2 when taxiing, the distribution coefficient GF ₃ is set equal to the nineteenth predetermined value (0.6).

[0055] Thus, if the absolute value of the steering angle δ when steering is equal to or greater than the first predetermined steering angle δ1 when taxiing, the final axial force calculating unit 11Bc in one embodiment of the present disclosure sets the distribution coefficient GF _3b (axial distribution coefficient GF direct coupling force T _FF ) is smaller than the distribution coefficient for the case in which the absolute value of the steering angle δ when taxiing is less than the first predetermined steering angle δ1 when taxiing. Accordingly, for example, when the steering angle δ is increased while steering, and the estimated axial force axial force T _{FF is} deteriorating, the finite axial force calculating unit 11Bc in one embodiment of the present disclosure allows an increase in the coefficient of (1-GF) axial force distribution T _{FB of the} inverse communication. Therefore, the final axial force calculating unit 11Bc in one embodiment of the present disclosure allows the application of a more appropriate taxiing force.

[0056] FIG. 18 is a graph representing a control card M9.

Here, as a method for setting the distribution coefficient GF ₄ , for example, a method for reading the distribution coefficient GF ₄ corresponding to the absolute value of the angular taxiing speed dδ / dt from the control map M9 can be used. As a control card M9, for example, a card is provided in which distribution coefficients GF ₄ are recorded corresponding to the absolute values of the angular velocity dδ / dt of taxiing. Specifically, as illustrated in FIG. 18, on the control map M9, in a range in which the absolute value of the angular velocity dδ / dt of steering is equal to or greater than 0 and less than the fourth predetermined angular velocity dδ ₄ / dt of steering (> 0), the distribution coefficient GF ₄ is set equal to the twentieth predetermined value ( for example, 1.0) regardless of the absolute value of the angular velocity dδ / dt of taxiing. As the fourth predetermined angular taxiing speed dδ ₄ / dt, for example, the angular taxiing speed dδ / dt can be used, by which the estimated accuracy of the axial direct coupling force T _FF starts to deteriorate. In addition, on the control map M9, in a range in which the absolute value of the angular velocity dδ / dt of taxiing is equal to or greater than the fifth preset angular velocity dδ ₅ / dt of taxiing (> dδ ₄ / dt), the distribution coefficient GF ₄ is set to twenty first value (<the twentieth set value, for example, 0.0) regardless of the absolute value of the angular velocity dδ / dt taxiing. As the fifth predetermined angular taxiing speed dδ ₅ / dt, for example, the angular taxiing speed dδ / dt can be used, by which the estimated direct axial force T _{FF is} lower than the estimated axial feedback force T _FB . Additionally, on the control map M9, in a range in which the absolute value of the angular velocity dδ / dt of taxiing is equal to or greater than the fourth preset angular velocity dδ ₄ / dt of taxiing and less than the fifth preset angular velocity dδ ₅ / dt of taxiing, the distribution coefficient GF ₄ decreases linearly according to the absolute value of the angular velocity dδ / dt of taxiing. Specifically, on the control map M9, in a range in which the absolute value of the angular velocity dδ / dt of taxiing is equal to or greater than the fourth preset angular velocity dδ ₄ / dt of taxiing and less than the fifth preset angular velocity dδ ₅ / dt of taxiing, the distribution coefficient GF ₄ is set in in accordance with a linear function representing the relationship between the absolute value of the angular velocity dδ / dt taxiing and the distribution coefficient GF ₄ . In a linear function, when the absolute value of the angular velocity dδ / dt of taxiing is the fourth preset angular speed dδ ₄ / dt of steering, the distribution coefficient GF ₄ is set to the twentieth preset value (1,0), and when the absolute value of the angular velocity dδ / dt of taxiing is the fifth predetermined angular speed dδ ₅ / dt taxiing, the distribution coefficient GF ₄ is set equal to the twenty-first predetermined value (0,0).

[0057] Thus, if the absolute value of the angular velocity dδ / dt of taxiing is equal to or greater than the fourth predetermined angular velocity dδ ₄ / dt of taxiing, the final axial force calculation module 11Bc in one embodiment of the present disclosure sets the distribution coefficient GF ₄ (coefficient GF of the axial force distribution T _{FF of} direct coupling) is smaller than the distribution coefficient for the case in which the absolute value of the angular velocity dδ / dt of taxiing is less than the fourth predetermined angular velocity dδ ₄ / dt of taxiing. Accordingly, for example, when the steering angular velocity dδ / dt increases, and the estimated axial direct force T _{FF is} deteriorated, the final axial force calculating unit 11Bc in one embodiment of the present disclosure allows an increase in the axial force distribution coefficient T _FB (1-GF) feedback. Therefore, the final axial force calculating unit 11Bc in one embodiment of the present disclosure allows the application of a more appropriate taxiing force.

[0058] Accordingly, the final axial force calculating unit 11Bc sets the direct axial force T _FF to the final axial force when the absolute value of the axial force difference is less than the first predetermined axial force difference Z1, the absolute value of the lateral acceleration Gy is less than the first lateral acceleration Gy ₁ , the absolute the value of the vehicle speed V is equal to or greater than the fourth predetermined vehicle speed V ₄ , the absolute value of the steering angle δ when taxiing is less than the first specified steering angle δ1 when taxiing, and abs The absolute value of the angular velocity dδ / dt of taxiing is less than the fourth preset angular velocity dδ ₄ / dt of taxiing. In addition, the finite axial force calculation unit 11Bc sets the feedback axial force T _FB equal to the final axial force when at least one of the cases in which the absolute value of the axial force difference is equal to or greater than the second predetermined axial force difference Z2 is satisfied, case wherein the absolute value of the lateral acceleration Gy is equal to or greater than a second predetermined lateral acceleration Gy _2, and the case in which the absolute value of the angular velocity dδ / dt is equal to or exceeds the steering fifth predetermined angular speed ₅ dδ / dt handlebars tions. Additionally, the final axial force calculation unit 11Bc sets the summed result to the final axial force, the summed result obtained by summing the multiplied value obtained by multiplying the direct coupling axial force T _FF by the distribution coefficient GF and the multiplied value obtained by multiplying the axial force T _FB feedback on the distribution coefficient (1-GF), when the absolute value of the difference between the axial forces is equal to or exceeds the first specified difference Z1 of the axial forces and less than of a given axial force difference Z2, the absolute value of the transverse acceleration Gy is equal to or greater than the first specified transverse acceleration Gy ₁ and less than the second specified transverse acceleration Gy ₂ , the absolute value of the vehicle speed V is less than the fourth specified speed of the vehicle V ₄ , the absolute value of the angle of rotation δ when taxiing, equal to or greater than the first specified angle of rotation δ1 when taxiing, and the absolute value of the angular velocity dδ / dt of taxiing is equal to or greater than the fourth specified angular speed dδ ₄ / dt p elation.

[0059] Accordingly, when the vehicle A is subjected to a situation in which μ the road surface for the road is high (dry road surface), the vehicle speed V is high, the steering angle δ is small, and the angular taxi speed dδ / dt is the small (hereinafter referred to as the “special situation”) module 11Bc calculates the final axial force sets the axial force T _FF direct coupling equal to the final axial force. Here, since the axial force T _{FF of the} direct coupling does not reflect the influence of the lateral force Fd on the tires, the axial force T _{FF of the} direct coupling smoothly changes regardless of a change in the surface of the road. Therefore, the final axial force calculating unit 11Bc allows the feeling of stable steering to be achieved when the vehicle A is in a special situation. In contrast, the final axial force calculating unit 11Bc sets the axial feedback force T _FB or the summed result obtained by summing the direct axial force T _FF and the axial feedback force T _FB when the vehicle A is in a situation (hereinafter, called a “normal situation”) other than a “special situation”. Here, since the influence of the lateral force Fd on the tires applied to the steered wheels 2 is reflected in the axial feedback force T _FB , the axial feedback force T _FB varies depending on the change in the road surface or the state of the vehicle. Accordingly, when the vehicle A is in the normal state, the final axial force calculating unit 11Bc provides a steering sensation similar to the steering sensation for a mechanical type of steering control device in which the steering wheel 1 and the steering wheels 2 are mechanically engaged with each other, so that A natural feel when taxiing.

[0060] Returning to FIG. 3, the steering force and axial force conversion unit 11Bd calculates the target steering force based on the final axial force, which is calculated by the final axial force calculating unit 11Bc. The target steering reaction is the target value of the steering reaction. As a method of calculating the target reaction force when taxiing, for example, a method of reading the target reaction force when taxiing, corresponding to the vehicle speed V and the final axial force, from the control map M10 can be used. The control map M10 is a map in which the target steering reaction force corresponding to the final axial force is recorded for each vehicle speed V.

FIG. 19 is a graph representing a control card M10.

As illustrated in FIG. 19, a control map M10 is set for each vehicle speed V. In addition, on the control map M10, the target steering reaction force is greater as the final axial force becomes larger.

Returning to FIG. 3, the target reaction force current calculating unit 11Be calculates the target electric reaction force current in accordance with the following expression (13) based on the target steering reaction force calculated by the taxiing reaction force conversion unit 11Bd and the axial force. Then, the reaction force target current calculating unit 11Be outputs the calculation result to the engine driving unit 9C to generate the reaction force.

Target reaction force current = target reaction force during taxiing * gain ... (13)

[0061] It should be noted that in one embodiment of the present disclosure, an example is described in which the target reaction force current calculating unit 11Be calculates the target steering force when taxiing based on the taxiing reaction force converting module 11Bd and the axial force. However, a different configuration may be used. For example, the target reaction force current calculating unit 11Be can correct the target reaction force when taxiing by adding the corrective reaction force, the reaction force at full stop, and the like. with the target steering reaction force calculated by the steering force conversion and axial force conversion unit 11Bd so as to calculate the target electric current of the reaction force based on the target steering reaction force, which is adjusted. As an example, a corrective reaction force is provided, a reaction force when taxiing, applied when the target reaction force when taxiing is adjusted. In addition, as a reaction force at full stop, an example is the reaction force when taxiing, applied when the angle of rotation θ becomes maximum.

[0062] The axial feedback force correction module 11Bf determines whether or not the vehicle A is reversing based on the position of the gear lever, which is read by the gear shift position sensor 12. Here, when it is determined that the shift lever is in the R-range (reverse position), the axial feedback force correction unit 11Bf determines that the vehicle A is reversing. Then, when it is determined that the vehicle A is reversing, the axial feedback force correction unit 11Bf outputs the axial direct force T _FF calculated by the axial direct force calculating unit 11Ba to the final axial force calculating unit 11Bc as the axial force T _FB feedback. On the other hand, when it is determined that the vehicle A is not reversing, the axial feedback force correction unit 11Bf outputs the axial feedback force T _FB calculated by the axial feedback force calculating unit 11Bb to the final axial force calculating unit 11Bc without changes.

[0063] Work and the like.

The following describes the operation of the steering control device of vehicle A.

While the vehicle A is moving, it is assumed that the driver controls the steering wheel 1. Then, the control parameter calculating section 11 calculates the steering angle θ * based on the steering angle δ while steering and the vehicle speed V (the target steering angle calculating section 11A Fig. 2). Then, the control parameter calculating unit 11 calculates the electric current of the target rotation angle based on the subtraction obtained by subtracting the actual rotation angle θ from the target rotation angle θ *, which is calculated (the rotation target calculation module 11C of FIG. 2). Accordingly, the control unit 8 rotates the steered wheels 2 upon rotation based on the working value of the steering wheel 1.

[0064] At the same time, the control parameter calculation unit 11 calculates the direct coupling axial force T _FF based on the steering angle δ and the vehicle speed V (the direct coupling axial force calculating unit 11Ba of FIG. 3). Then, the control parameter calculating unit 11 calculates the axial current based on the electric current of the rotation angle (the axial current calculating unit 11Bba in FIG. 11). Then, the control parameter calculation unit 11 calculates an axial transverse force G based on the lateral acceleration Gy (the mixed axial force calculation unit 11Bbb of FIG. 11). After that, the control parameter calculation unit 11 calculates the axial force of the angular yaw rate based on the angular yaw rate γ and the vehicle speed V (the mixed axial force calculation module 11Bbb of FIG. 11). Then, the control parameter calculating unit 11 calculates the mixed axial force T _BR based on the value obtained by multiplying the distribution coefficient K2 by the axial electric current strength, which is calculated by the value obtained by multiplying the distribution coefficient K1 by the axial transverse force G, and the value obtained by multiplying the distribution coefficient K3 by the axial force of the angular yaw rate (mixed axial force calculation module 11Bbb of FIG. 11). The coefficients K1, K2 and K3 of the distribution of the axial force of the transverse G, the axial force of the electric current and the axial force of the angular velocity of yaw are set equal to 0.6: 0.3: 0.1. Then, the control parameter calculation unit 11 mixes the axial electric current strength calculated and the mixed axial force T _BR with GB: (1-GB) and sets the distributed result to the axial feedback force T _FB (the axial feedback force calculating unit 11Bb of FIG. . 3).

[0065] Next, the control parameter calculation unit 11 refers to the control card M6 of FIG. 15 and calculates a distribution coefficient GF ₁ based on the absolute value of the difference in axial forces (final axial force calculation module 11Bc of FIG. 3). Then, the control parameter calculation unit 11 refers to the control card M7 of FIG. 16 and calculates a distribution coefficient GF ₂ based on the absolute value of the lateral acceleration Gy (finite axial force calculation module 11Bc of FIG. 3). After that, the control parameter calculating module 11 refers to the control cards M8a and Mb of FIG. 17 and calculates the distribution coefficients GF _3a , GF _3b, and GF ₃ based on the absolute value of the vehicle speed V and the absolute value of the steering angle δ when steering (final axial force calculation module 11Bc of FIG. 3). Then, the control parameter calculation unit 11 refers to the control card M9 of FIG. 18 and calculates a distribution coefficient GF ₄ based on the absolute value of the angular taxiing speed dδ / dt (final axial force calculation module 11Bc of FIG. 3). Then, the control parameter calculating unit 11 multiplies the smaller of the distribution coefficient GF ₁ and the distribution coefficient GF ₂ that are calculated, the distribution coefficient GF ₃ and the distribution coefficient GF ₄ , and sets the multiplication result as the distribution coefficient GF. Next, the control parameter calculating unit 11 mixes the direct coupling axial force T _FF and the feedback axial force T _FB , which are calculated with 1: (1-GF), and calculates the final axial force (the final axial force calculating module 11Bc of FIG. 3) . Then, the control parameter calculating module 11 calculates the target steering reaction force based on the final axial force, which is calculated (the taxiing reaction force and axial force conversion module 11Bd in FIG. 3). Then, the control parameter calculating unit 11 calculates the target electric current of the reaction force based on the target taxiing reaction force, which is calculated (the calculating target electric current of the reaction force 11Be of FIG. 3). Next, the control parameter calculating module 11 drives the motor 9A to generate a reaction force based on the target electric current of the reaction force, which is calculated (the motor driving module 9C for generating the reaction force of FIG. 2). Accordingly, the reaction force control unit 9 applies a reaction force when taxiing to the steering wheel 1.

[0066] Thus, the steering control device in one embodiment of the present disclosure mixes the axial direct coupling force T _FF and the axial feedback force T _FB with the distribution coefficients GF ₁ , GF ₂ , GF ₃ and GF ₄ based on the difference in axial forces, lateral acceleration Gy, vehicle speed V, steering angle δ and taxiing angle dδ / dt in order to specify the final axial force. Then, the steering control device in one embodiment of the present disclosure applies a steering force upon taxiing based on the final axial force that is specified. Accordingly, since the steering control device in one embodiment of the present disclosure mixes the axial direct coupling force T _FF and the axial feedback force T _FB with the distribution coefficients GF ₁ , GF ₂ , GF ₃ and GF ₄ based on the difference in axial forces, lateral acceleration Gy , vehicle speed V, steering angle δ and steering angular speed dδ / dt, so that the axial direct coupling force T _FF and the axial feedback force T _FB can be distributed more appropriately. Therefore, the steering control device in one embodiment of the present disclosure allows the application of a more appropriate reaction force when taxiing.

[0067] In one embodiment of the present disclosure, steering wheel 1 of FIG. 1 corresponds to the steering wheel. Similarly, the rotary engine 8A and the rotary engine driving module 8C of FIG. 1 correspond to a rotary drive. In addition, the steering angle sensor 3 in FIG. 1 corresponds to a steering angle detection module. Additionally, the axial direct force calculating unit 11Ba of FIG. 1 corresponds to a module for calculating an axial direct coupling force. In addition, the transverse G sensor 6, the yaw rate sensor 7, and the rotational current detection module 8B of FIG. 1 correspond to a module for detecting values characterizing a state. Additionally, the axial feedback force calculating unit 11Bb in FIG. 3 and the axial feedback force calculation module 11Bbe of FIG. 11 correspond to a module for calculating an axial feedback force. In addition, the vehicle speed sensor 5 of FIG. 1 corresponds to a vehicle speed detection module. Additionally, the final axial force calculation module 11Bc of FIG. 3 corresponds to a module for detecting an angular taxi speed. In addition, transverse G sensor 6 of FIG. 1 and the final axial force calculation module 11Bc of FIG. 3 correspond to the module for setting the final axial force. In addition, the reaction force generating engine 9A and the engine driving module 9C for generating the reaction force in FIG. 1 and the reaction force target current calculating unit 11B in FIG. 2 correspond to a reaction force drive.

[0068] Advantages in the Present Disclosure

The following advantages are provided in one embodiment of the present disclosure.

(1) The control parameter calculating unit 11 mixes the axial direct coupling force T _FF and the feedback axial force T _FB with the distribution coefficients GF ₁ , GF ₂ , GF ₃ and GF ₄ based on the difference in axial forces, lateral acceleration Gy, vehicle speed V , steering angle δ and taxiing angular speed dδ / dt in order to specify the final axial force. Then, the control parameter calculating unit 11 applies a reaction force when taxiing based on the final axial force that is specified.

In such a configuration, since the axial direct coupling force T _FF and the feedback axial force T _FB are distributed with the distribution coefficients GF ₁ , GF ₂ , GF ₃ and GF ₄ based on the difference in axial forces, lateral acceleration Gy, vehicle speed V, angle δ steering angle and steering angular speed dδ / dt, so that the axial direct coupling force T _FF and the axial feedback force T _FB can be distributed more appropriately.

Thus, in such a configuration, a more appropriate reaction force when taxiing can be applied.

[0069] (2) If the absolute value of the axial force difference is equal to or greater than the first predetermined axial force difference Z1, the control parameter calculation module 11 sets the distribution coefficient GF (distribution coefficient GF ₁ ) of the direct coupling axial force T _{FF to a} smaller distribution coefficient for the case , in which the absolute value of the difference between the axial forces is less than the first specified difference Z1 of the axial forces.

In such a configuration, for example, when the estimated accuracy of the axial direct coupling force T _FF deteriorates and the difference in axial forces increases, the distribution coefficient (1-GF) of the axial feedback force T _FB may increase. Therefore, a more appropriate reaction force during taxiing can be applied.

[0070] (3) If the absolute value of the lateral acceleration Gy is equal to or greater than the first predetermined lateral acceleration Gy ₁ , the control parameter calculation module 11 sets the distribution coefficient GF (distribution coefficient GF ₂ ) of the direct coupling axial force T _{FF to a} smaller distribution coefficient for the case in which the absolute value of the lateral acceleration Gy is less than the first predetermined lateral acceleration Gy ₁ .

In such a configuration, for example, when the lateral acceleration Gy increases, and the estimated accuracy of the direct axial force T _FF deteriorates, the distribution coefficient (1-GF) of the axial feedback force T _FB may increase. Therefore, a more appropriate reaction force during taxiing can be applied.

[0071] (4) If the absolute value of the vehicle speed V is less than the fourth predetermined vehicle speed V ₄ , the control parameter calculation unit 11 sets the distribution coefficient GF (distribution coefficient GF ₃ ) of the direct coupling axial force T _{FF to a} smaller distribution coefficient for the case in which the absolute value of the vehicle speed V exceeds a fourth predetermined vehicle speed V ₄ .

In such a configuration, for example, when the vehicle speed V decreases and the estimated accuracy of the direct axial force T _FF deteriorates, the distribution coefficient (1-GF) of the axial feedback force T _FB may increase. Therefore, a more appropriate reaction force during taxiing can be applied.

[0072] (5) If the absolute value of the steering angle δ when steering is equal to or greater than the first predetermined steering angle δ1 when taxiing, the control parameter calculating unit 11 sets the distribution coefficient GF (distribution coefficient GF ₃ ) of the direct coupling axial force T _FF less than the coefficient distribution for the case in which the absolute value of the angle of rotation δ when taxiing is less than the first specified angle δ1 of rotation when taxiing.

In such a configuration, for example, when the steering angle δ is increased during steering and the estimated accuracy of the direct axial force T _FF deteriorates, the distribution coefficient (1-GF) of the axial feedback force T _FB may increase. Therefore, a more appropriate reaction force during taxiing can be applied.

[0073] (6) If the absolute value of the angular velocity dδ / dt of steering is equal to or greater than the fourth predetermined angular velocity dδ ₄ / dt of steering, the control parameter calculation module 11 sets the distribution coefficient GF (distribution coefficient GF ₄ ) of the direct axial force T _FF communication smaller allocation coefficient for the case in which the absolute value of the angular velocity dδ / dt is less than the fourth predetermined steering angular velocity ₄ dδ / dt taxiing.

In such a configuration, for example, when the angular steering speed dδ / dt increases, and the estimated accuracy of the axial direct force T _FF deteriorates, the distribution coefficient (1-GF) of the axial force distribution T _FB feedback can be increased. Therefore, a more appropriate reaction force during taxiing can be applied.

This application claims the priority of patent application (Japan) No. 2013-3874 (filed January 11, 2013), which is fully contained in this document by reference.

In this document, although a limited number of illustrative embodiments are described, it should be obvious that the present disclosure is not limited to them, and modifications and adaptations to each of the embodiments based on the above disclosure may be made by those skilled in the art.

Legend List

[0074] 1 - steering wheel (steering wheel)

3 - steering angle sensor during taxiing (steering angle detection module during taxiing)

5 - vehicle speed sensor (vehicle speed detection module)

6 - transverse G sensor (module for detecting values characterizing the state, module for setting the final axial force)

7 - yaw rate sensor (module for detecting values characterizing a state)

8A - engine for forming a rotation angle (rotation angle drive)

8B - module for determining the angle of rotation current (module for detecting values characterizing the state)

8C — engine driving module for forming a rotation angle (rotation angle drive)

9A — engine for generating reaction force (reaction force drive)

9C — engine driving module for generating a reaction force (reaction force drive)

11B is a module for calculating the target current of the reaction force (reaction force drive)

11Ba is a module for calculating the axial force of the direct coupling (module for calculating the axial force of the direct coupling)

11Bb - axial feedback force calculation module (axial feedback force calculation module)

11Bbe - module for calculating the axial feedback force (module for calculating the axial feedback force)

11Bc - module for calculating the final axial force (module for setting the final axial force)

Claims (53)

1. A steering control device comprising: - a steering wheel mechanically separated from the steered wheels; - a module for detecting a steering angle when taxiing, configured to detect a steering angle when steering; - a rotary drive configured to rotate the steered wheels according to the steering angle when taxiing detected by the steering angle detection module while taxiing; - a module for calculating an axial direct coupling force, configured to calculate an axial direct coupling force, which is a force generated in the steering system, based on the steering angle when taxiing detected by the steering angle detection module while taxiing; - a module for detecting values characterizing a state, configured to detect a value characterizing a state of a vehicle, which varies depending on a lateral force on tires applied to steered wheels; - a module for calculating an axial feedback force, configured to calculate an axial feedback force, which is a force generated in the steering system, based on a value characterizing a state of a vehicle detected by a module for detecting values characterizing a state; - a final axial force setting module, configured to set a final axial force, which is a force generated in the steering system, by distributing the axial direct coupling force calculated by the axial direct coupling force calculating module and the axial feedback force calculated by a module for calculating an axial feedback force; and - a reaction force drive configured to apply a reaction force when taxiing based on a final axial force specified by a final axial force setting module, - in this case, the final axial force setting module is configured to set the distribution coefficient of the axial direct coupling force less if there is a difference in axial forces between the axial direct coupling force and the axial feedback force, compared with the distribution coefficient if there is no axial difference forces. 2. A steering control device comprising: - a steering wheel mechanically separated from the steered wheels; - a module for detecting a steering angle when taxiing, configured to detect a steering angle when steering; - a rotary drive configured to rotate the steered wheels according to the steering angle when taxiing detected by the steering angle detection module while taxiing; - a module for calculating an axial direct coupling force, configured to calculate an axial direct coupling force, which is a force generated in the steering system, based on the steering angle when taxiing detected by the steering angle detection module while taxiing; - a module for detecting values characterizing a state, configured to detect a value characterizing a state of a vehicle, which varies depending on a lateral force on tires applied to steered wheels; - a module for calculating an axial feedback force, configured to calculate an axial feedback force, which is a force generated in the steering system, based on a value characterizing a state of a vehicle detected by a module for detecting values characterizing a state; - a final axial force setting module, configured to set a final axial force, which is a force generated in the steering system, by distributing the axial direct coupling force calculated by the axial direct coupling force calculating module and the axial feedback force calculated by a module for calculating an axial feedback force; - a reaction force drive configured to apply a reaction force when taxiing based on a final axial force specified by a final axial force setting module; and - a lateral acceleration detection module configured to detect lateral acceleration applied to the vehicle, - in this case, if the absolute value of the lateral acceleration is equal to or exceeds the specified value, the final axial force setting module is configured to set the distribution coefficient of the axial direct coupling force less than the distribution coefficient if the absolute value of the lateral acceleration is less than the specified value. 3. A steering control device comprising: - a steering wheel mechanically separated from the steered wheels; - a module for detecting a steering angle when taxiing, configured to detect a steering angle when steering; - a rotary drive configured to rotate the steered wheels according to the steering angle when taxiing detected by the steering angle detection module while taxiing; - a module for calculating an axial direct coupling force, configured to calculate an axial direct coupling force, which is a force generated in the steering system, based on the steering angle when taxiing detected by the steering angle detection module while taxiing; - a module for detecting values characterizing a state, configured to detect a value characterizing a state of a vehicle, which varies depending on a lateral force on tires applied to steered wheels; - a module for calculating an axial feedback force, configured to calculate an axial feedback force, which is a force generated in the steering system, based on a value characterizing a state of a vehicle detected by a module for detecting values characterizing a state; - a final axial force setting module, configured to set a final axial force, which is a force generated in the steering system, by distributing the axial direct coupling force calculated by the axial direct coupling force calculating module and the axial feedback force calculated by a module for calculating an axial feedback force; - a reaction force drive configured to apply a reaction force when taxiing based on a final axial force specified by a final axial force setting module; and - a vehicle speed detection module, configured to detect a vehicle speed, - in this case, if the absolute value of the vehicle speed is less than the specified value, the final axial force setting module is configured to set the distribution coefficient of the direct axial force less than the distribution coefficient if the absolute value of the vehicle speed is equal to or exceeds the specified value . 4. A steering control device comprising: - a steering wheel mechanically separated from the steered wheels; - a module for detecting a steering angle when taxiing, configured to detect a steering angle when steering; - a rotary drive configured to rotate the steered wheels according to the steering angle when taxiing detected by the steering angle detection module while taxiing; - a module for calculating an axial direct coupling force, configured to calculate an axial direct coupling force, which is a force generated in the steering system, based on the steering angle when taxiing detected by the steering angle detection module while taxiing; - a module for detecting values characterizing a state, configured to detect a value characterizing a state of a vehicle, which varies depending on a lateral force on tires applied to steered wheels; - a module for calculating an axial feedback force, configured to calculate an axial feedback force, which is a force generated in the steering system, based on a value characterizing a state of a vehicle detected by a module for detecting values characterizing a state; - a final axial force setting module, configured to set a final axial force, which is a force generated in the steering system, by distributing the axial direct coupling force calculated by the axial direct coupling force calculating module and the axial feedback force calculated by a module for calculating an axial feedback force; and - a reaction force drive configured to apply a reaction force when taxiing based on a final axial force specified by a final axial force setting module, - in this case, if the absolute value of the angle of rotation when taxiing is equal to or exceeds a predetermined value, the final axial force setting module is configured to set the distribution coefficient of the axial direct force less than the distribution coefficient if the absolute value of the angle of rotation when taxiing is less set value. 5. A steering control device comprising: - a steering wheel mechanically separated from the steered wheels; - a module for detecting a steering angle when taxiing, configured to detect a steering angle when steering; - a rotary drive configured to rotate the steered wheels according to the steering angle when taxiing detected by the steering angle detection module while taxiing; - a module for calculating an axial direct coupling force, configured to calculate an axial direct coupling force, which is a force generated in the steering system, based on the steering angle when taxiing detected by the steering angle detection module while taxiing; - a module for detecting values characterizing a state, configured to detect a value characterizing a state of a vehicle, which varies depending on a lateral force on tires applied to steered wheels; - a module for calculating an axial feedback force, configured to calculate an axial feedback force, which is a force generated in the steering system, based on a value characterizing a state of a vehicle detected by a module for detecting values characterizing a state; - a final axial force setting module, configured to set a final axial force, which is a force generated in the steering system, by distributing the axial direct coupling force calculated by the axial direct coupling force calculating module and the axial feedback force calculated by a module for calculating an axial feedback force; - a reaction force drive configured to apply a reaction force when taxiing based on a final axial force specified by a final axial force setting module; and - a module for detecting the angular speed of taxiing, configured to detect the angular speed of taxiing of the steering wheel, - in this case, if the absolute value of the angular speed of taxiing is equal to or exceeds a predetermined value, the final axial force setting module is configured to set the distribution coefficient of the axial direct force less than the distribution coefficient if the absolute value of the angular speed of taxiing is less than the specified value .

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